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Many folks have wished to inquire about why their Sullair air compressor is not turning on and other questions along those same lines. This article will present some of the reasons this may happen and provide Sullair air compressor troubleshooting suggestions to resolve those issues and existing reader problems.
Table of Contents
- Reasons Why Your Sullair Air Compressor Won’t Start
- Additional Sullair Air Compressors Pages On About-Air-Compressors.com
- Reader Questions and Responses
Reasons Why Your Sullair Air Compressor Won’t Start
The main reasons as to why your Sullair air compressor hums but won’t start are likely to be due to any of the following reasons summarized in the table below:
Issue | Advice |
---|---|
Power issue | Avoid using power bars and power strips. |
Faulty pressure switch | Unplug the Sullair compressor from the electrical outlet before opening the drain valve, releasing the air from the tank down to zero, and then closing the drain. |
Fuse or breaker blows | Circuit breakers will trip off when a power surge blows their fuses. If the fuses are faulty, you will need fuse replacements. |
Faulty unloader valve | Check unloader valve, if faulty pressure switch may not work. |
Faulty thermal overload switch | Check the thermal overload switch to ensure it is working correctly. |
Insufficient oil | Check the oil level, and inspect the pump area for any potential leaks. |
Please visit our Air Compressor Won’t Start – Ways to Fix Air Compressor Won’t Turn On Problems guide for more detailed Sullair air compressor troubleshooting & fixes!
Additional Sullair Air Compressors Pages On About-Air-Compressors.com
- Sullair Compressor Fault Codes – Sullair Air Compressor Displaying Errors
- Sullair Compressor Oil – Changing It, Which To Use & How Much To Use
Reader Questions and Responses
Sullair Air Compressor Won t Turn On – Sullair Air Compressor Troubleshooting
Question
In automatic and manual, the compressor will not start, saying it is waiting for blowdown.
The manual says the sump pressure is too high, the indication is around 15 pounds. It seems like the blowdown is working, but we might have a check valve leaking back, and potentially a pressure detection issue.
With the discharge valve close, we can get pressure down to 6 pounds.
I wonder if we should take the check valve out and try to clean it up? Any other advice would be great.
Response
Any particular model you’re dealing with?
Question
It is a Sullair Model 7507, we had it serviced and they replaced the pressure transducer P1 and rebuilt the MPV.

Response
So, did that rebuild and transducer fix it, or was that before you first wrote?
Have you checked the check valve, too?
Question
Jeff did you figure out why it was saying waiting for blowdown I am having the same issue. Dustin
Question
The pressure transducer P1 was bad, and we had some leak back from the air system. Jeff
Response
Hey Jeff, thanks for taking the time to come back and reply to Dustin.
It’s great when my site works the way it’s supposed to… compressor folks helping other compressor users.
If you have any questions regarding the Sullair air compressor won’t turn on, please leave a comment below, with a photo if applicable, so that someone can help you!